The present invention relates to a radiation detector that comprises at least two optically connected light receiving elements.
Conventionally, a photomultiplier tube has been applied to a radiation detector as a light receiving element having multiple channels (output terminals) (e.g., Patent Document 1), but recently a semiconductor light receiving element is being applied thereto as the light receiving element having one channel (output terminal) for a miniaturization purpose. In addition, according to Patent Document 1: JP2005-037363, reflection materials are in-place between adjacent scintillators to each other, forming a scintillator array to improve capability for incident location discrimination of a γ-ray and capability for detection thereof.
The inventor sets forth the structure of a conventional radiation detector referring to FIG. 9, FIG. 10. FIG. 9 is a side view illustrating a structure of the conventional radiation detector. FIG. 10 is a schematic view illustrating amplifiers and timing generation circuits relative to the conventional radiation detector. Referring to FIG. 9, the radiation detector 100 comprises scintillator arrays 110 consisting of a plurality of scintillators 111 (longitudinal 20×lateral 20=400 in FIG. 9) and a plurality of semiconductor light receiving elements 120, of which the number is smaller than the number of scintillators 111 (longitudinal 8×lateral 8=64 in FIG. 9). The semiconductor light receiving elements 120 optically connects at least two scintillators 111 (three scintillators in FIG. 9).
Referring to FIG. 10, the radiation detector 100 further comprises the amplifiers that amplify the signal obtained by the respective semiconductor light receiving elements 120 (referring to FIG. 9), wherein the number of the amplifiers that connect the timing generation circuit 140 is equal to the number of the one-on-one semiconductor light receiving elements 120 (64 in FIG. 10). The timing generation circuit 140 comprises an accumulator 141 that adds all signals amplified respectively by the amplifiers 130 and a trigger generation circuit 142 that generates a trigger of the signals added by the accumulator 141. A timing signal is generated based on the trigger generated by the trigger generation circuit 142. Specifically, referring to FIG. 10, the individual amplifier 130 is in-place per channel of the semiconductor light receiving element and the accumulator 141 adds all outputs (amplified signals) of the amplifier 130 and generates the timing signal.